1uke_
Posts: 74
Joined: Thu Jul 07, 2016 9:19 pm

Need help with composite output

Fri Oct 25, 2019 9:25 pm

Hello,

I am attempting to get teefax working which requires me to output video via the composite cable.

I am using a Raspberry Pi 2b+ running Raspbian Stretch. My TV uses the PAL UK signal.

I have modified the /boot/config.txt file to have the following

sdtv_mode=2
#hdmi_force_hotplug=1

I have put my full config file here - https://pastebin.com/c3KVASK5

Can any one suggest my composite video isn't working and what I might do to resolve it?

Thank you in advance :)
Last edited by 1uke_ on Fri Oct 25, 2019 9:30 pm, edited 2 times in total.

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rpiMike
Posts: 975
Joined: Fri Aug 10, 2012 12:38 pm
Location: Cumbria, UK

Re: Need help with composite output

Fri Oct 25, 2019 9:27 pm

Which model of Raspberry Pi are you using?

Which composite format does your TV use eg PAL,NTSC?

1uke_
Posts: 74
Joined: Thu Jul 07, 2016 9:19 pm

Re: Need help with composite output

Fri Oct 25, 2019 9:29 pm

rpiMike wrote:
Fri Oct 25, 2019 9:27 pm
Which model of Raspberry Pi are you using?
Thanks for the heads up Mike, (I really should know better!)

I have updated the original post above to include that I am running a Raspberry Pi 2b+ with Raspbian Stretch. And that my TV uses PAL UK

Thanks again for mentioning that I forgot this vital information :/

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rpiMike
Posts: 975
Joined: Fri Aug 10, 2012 12:38 pm
Location: Cumbria, UK

Re: Need help with composite output

Fri Oct 25, 2019 9:31 pm

Are you using a cable that specifies compatible with the Pi?

https://thepihut.com/products/av-compos ... 3-x-rca-3m

1uke_
Posts: 74
Joined: Thu Jul 07, 2016 9:19 pm

Re: Need help with composite output

Fri Oct 25, 2019 9:33 pm

rpiMike wrote:
Fri Oct 25, 2019 9:31 pm
Are you using a cable that specifies compatible with the Pi?

https://thepihut.com/products/av-compos ... 3-x-rca-3m
I'm not. It's just a random cable I got from eBay ........ (I think I know where this might be going) :D

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rpiMike
Posts: 975
Joined: Fri Aug 10, 2012 12:38 pm
Location: Cumbria, UK

Re: Need help with composite output

Fri Oct 25, 2019 9:35 pm

I suggest you buy a recommended cable - there are at least 4 different wiring combinations.

If you have a multimeter you can check your cable : https://www.youtube.com/watch?v=UEWs_bxDWic
Last edited by rpiMike on Fri Oct 25, 2019 9:37 pm, edited 1 time in total.

drgeoff
Posts: 9912
Joined: Wed Jan 25, 2012 6:39 pm

Re: Need help with composite output

Fri Oct 25, 2019 9:36 pm

A large proportion of the difficulties with composite video are caused by not using an appropriately wired cable between the 3.5mm socket on the RPi and the TV.

See eg https://www.raspberrypi.org/forums/view ... 22#p653422 for details.

klricks
Posts: 6614
Joined: Sat Jan 12, 2013 3:01 am
Location: Grants Pass, OR, USA
Contact: Website

Re: Need help with composite output

Sat Oct 26, 2019 12:07 am

1uke_ wrote:
Fri Oct 25, 2019 9:33 pm
rpiMike wrote:
Fri Oct 25, 2019 9:31 pm
Are you using a cable that specifies compatible with the Pi?

https://thepihut.com/products/av-compos ... 3-x-rca-3m
I'm not. It's just a random cable I got from eBay ........ (I think I know where this might be going) :D
If you have the very common camcorder cable then connect RED of the cable to YELLOW on the TV.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.

fruitoftheloom
Posts: 21049
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: Need help with composite output

Sat Oct 26, 2019 5:02 am

1uke_ wrote:
Fri Oct 25, 2019 9:29 pm
rpiMike wrote:
Fri Oct 25, 2019 9:27 pm
Which model of Raspberry Pi are you using?
Thanks for the heads up Mike, (I really should know better!)

I have updated the original post above to include that I am running a Raspberry Pi 2b+ with Raspbian Stretch. And that my TV uses PAL UK

Thanks again for mentioning that I forgot this vital information :/

There is no 2B+ model, you are mistaken:

https://www.raspberrypi.org/documentati ... /README.md


Regards composite out, test the cable:

https://www.raspberrypi-spy.co.uk/2014/ ... ideo-jack/
Retired disgracefully.....
This at present is my daily "computer" https://www.asus.com/us/Chrome-Devices/Chromebit-CS10/

hippy
Posts: 6223
Joined: Fri Sep 09, 2011 10:34 pm
Location: UK

Re: Need help with composite output

Sat Oct 26, 2019 1:43 pm

1uke_ wrote:
Fri Oct 25, 2019 9:25 pm
I am using a Raspberry Pi 2b+ running Raspbian Stretch.
Presumably you mean a "Pi 2 Model B Version 1.2" which uses a BCM2837 ( perhaps even a BCM2837B these days ) rather than the BCM2836 fitted to the original 2B boards.

I also tend to think of that as a "2B+" to discriminate between the two but that is not its official designation.

There is no reason I can see why composite wouldn't work with any 2B and would also suspect the problem being an incorrectly wired connector cable.

About a third of the 3.5mm jack to video cables I have are directly compatible with the Pi wiring scheme, the others not. As suggested, you can use a resistance meter as a continuity checker to figure out how what you have is wired.

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